Comunidades de macroinvertebrados de riachos ainda apresentam um sinal biogeográfico

• Ano de defesa: 2019
• Autor(a) principal: Libório, Carlos Henrique Lopes
• Orientador(a): Bini, Luis Mauricio
• Banca de defesa: Bini, Luis Mauricio, Bortolini, Jascieli, Ortega, Jean Carlo Gonçalves
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Ecologia e Evolução (ICB)
• Departamento: Instituto de Ciências Biológicas - ICB (RG)
• País: Brasil
• Palavras-chave em Português: Regionalização biológica; Mudança de regimes; Força de classificação; Análises multivariadas; Impactos antrópicos
• Palavras-chave em Inglês: Bioregionalization; Regime shifts; Classification strength; Multivariate analysis; Anthropogenic impacts
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::ECOLOGIA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/9330

Ecosystems can have alternative stable states. In theory, temporal or spatial changes of a key environmental variable (e.g., phosphorus concentration), after a certain threshold, would cause rapid and abrupt changes in the state of an ecosystem (e.g. from oligo to eutrophic). The theory also predicts that feedback mechanisms hinder the return of an ecosystem to its original state, even when the change in the key variable is in the opposite direction. Detecting changes in ecological regimes is important to identify biogeographic boundaries and where environmental disturbances are occurring. The general objective of this work is to identify spatial changes in the state of streams macroinvertebrate communities. To do so, we used a large dataset covering the entire continental territory of the United States of America. We use a priori (ecoregions) and a posteriori classifications (based on environmental and anthropogenic variables) to quantify whether these typologies are representing the structure of macroinvertebrate communities. We calculated the classification strength considering ecoregions and environmental/anthropogenic variables as classification factors. We expected that these environmental/anthropogenic variables would have greater classification strength considering the strong environmental impacts on aquatic ecosystems. However, the classification strength of ecoregions was much higher than those of environmental/anthropogenic variables. We also found that areas of abrupt changes in communities are in part coincident with transitional zones between ecoregions. Therefore, our results indicate that there is still a clear biogeographic sign on macroinvertebrate communities, despite the strong anthropogenic environmental changes that aquatic ecosystems have undergone.